Such crane controller is known from DE 10 2008 024513 A1. There is provided a prediction device which predicts a future movement of the cable suspension point with reference to the determined current heave movement and a model of the heave movement, wherein a path controller of the load at least partly compensates the predicted movement of the cable suspension point.
For actuating the hoisting gear, DE 10 2008 024513 A1 creates a dynamic model of the hydraulically operated winch and the load hanging on the cable and creates a sequence control unit therefrom by inversion. For realizing a state control, unknown states of the load are reconstructed form a force measurement via an observer.
It is the object of the present disclosure to provide an improved crane controller.
According to the present disclosure, this object is solved in a first aspect by a crane controller according to claim 1 and in a second aspect by a crane controller according to claim 4.
In a first aspect, the present disclosure shows a crane controller for a crane which includes a hoisting gear for lifting a load hanging on a cable. The crane controller includes an active heave compensation which by actuating the hoisting gear at least partly compensates the movement of the cable suspension point and/or a load deposition point due to the heave. According to the present disclosure, it is provided that the heave compensation takes account of at least one constraint of the hoisting gear when calculating the actuation of the hoisting gear. By taking account of the constraint of the hoisting gear it is ensured that the hoisting gear actually can follow the control commands calculated due to the heave compensation and/or that the hoisting gear or the crane is not damaged by the actuation.
According to the present disclosure, the heave compensation can take account of a maximum admissible jerk. It thereby is ensured that the hoisting gear or the structure of the crane is not damaged by the actuation of the hoisting gear due to the heave compensation. Beside a maximum admissible jerk, a steady course of the jerk furthermore can be requested.
Alternatively or in addition, the heave compensation can take account of a maximum available power.
Alternatively or in addition, the heave compensation can take account of a maximum available acceleration. Such maximum available acceleration for example can result from the maximum power of the drive of the hoisting gear and/or the length of the cable unwound already and the weight force of the cable thereby acting on the hoisting gear and/or due to the load of the hoisting gear caused by the weight force to be lifted.
Furthermore alternatively or in addition, the heave compensation can take account of a maximum available velocity. The maximum available velocity for the heave compensation also can be obtained as described above with regard to the maximum available acceleration.
Furthermore, the crane controller can include a calculation operation which calculates the at least one constraint of the hoisting gear. For this purpose, the calculation operation can evaluate in particular sensor data and/or actuation signals. By the calculation operation, the currently applicable constraints of the hoisting gear can each be communicated to the heave compensation.
In particular, the constraints of the hoisting gear can change during a lift, which can be taken into account by the heave compensation according to the present disclosure.
The calculation operation each can exactly calculate a currently available at least one kinematically constrained quantity of the hoisting gear, in particular the maximum available power and/or velocity and/or acceleration of the hoisting gear. Advantageously, the calculation operation takes account of the length of the unwound cable and/or the cable force and/or the power available for driving the hoisting gear.
According to the present disclosure, the crane controller can be used for actuating a hoisting gear whose drive is connected with an energy accumulator. The amount of energy stored in the energy accumulator influences the power available for driving the hoisting gear. Advantageously, the amount of energy stored in the energy accumulator or the power available for driving the hoisting gear therefore is included in the calculation operation according to the present disclosure.
In particular, the hoisting gear according to the present disclosure can be actuated hydraulically, wherein a hydraulic energy accumulator is provided in the hydraulic circuit for driving the hoisting winch of the hoisting gear.
Alternatively, an electric drive can be used. The same can also be connected with an energy accumulator.
Advantageously, the crane controller furthermore comprises a path planning module which determines a trajectory with reference to the predicted movement of the cable suspension point and/or a load deposition point and by taking account of the constraints of the hoisting gear. According to the present disclosure the drive constraints, in particular the drive constraints with regard to the power, the velocity, the acceleration and/or the jerk can explicitly be taken into account when planning the trajectories. The trajectory in particular can be a trajectory of the position and/or velocity and/or acceleration of the hoisting gear.
Advantageously, the path planning module includes an optimization operation which with reference to the predicted movement of the cable suspension point and/or a load deposition point and by taking account of the constraint of the hoisting gear determines a trajectory which minimizes the residual movement of the load due to the movement of the cable suspension point and/or the differential movement between the load and the load deposition point due to the movement of the load deposition point. According to the present disclosure, the at least one drive constraint thus can be taken into account within the optimal control problem. Within the optimal control problem, the constraint of the drive in particular is taken into account with regard to power and/or velocity and/or acceleration and/or jerk.
The optimization operation advantageously calculates an optimal path with reference to a predicted vertical position and/or vertical velocity of the cable suspension point and/or a load deposition point, which by taking account of the kinematic constraints minimizes the residual movement and/or differential movement of the load.
In a second aspect, the present disclosure comprises a crane controller for a crane which includes a hoisting gear for lifting a load hanging on a cable. The crane controller comprises an active heave compensation which by actuating the hoisting gear at least partly compensates the movement of the cable suspension point and/or a load deposition point due to the heave. According to the present disclosure, the heave compensation includes a path planning module which with reference to a predicted movement of the cable suspension point and/or a load deposition point calculates a trajectory of the position and/or velocity and/or acceleration of the hoisting gear, which is included in a setpoint value for a subsequent control of the hoisting gear. Due to this structure of the heave compensation a particularly stable and easily realizable actuation of the hoisting gear is obtained. In particular, the unknown load position no longer must be reconstructed with great effort.
According to the present disclosure, the controller of the hoisting gear can feed back measured values to position and/or velocity of the hoisting winch. The path planning module hence specifies a position and/or velocity of the hoisting winch as setpoint value, which in the subsequent controller is matched with actual values.
Furthermore, it can be provided that the controller of the hoisting gear takes account of the dynamics of the drive of the hoisting winch by a pilot control. In particular, the pilot control can be based on an inversion of a physical model which describes the dynamics of the drive of the hoisting winch. In particular, the hoisting winch can be a hydraulically operated hoisting winch.
The first and the second aspect of the present disclosure each are protected separately by the present application and can each be realized separately and without the respective other aspect.
Particularly, however, the two aspects according to the present disclosure are combined with each other. In particular, it can be provided that the path planning module according to the second aspect of the present disclosure takes account of at least one constraint of the hoisting gear when determining the trajectory.
The crane controller according to the present disclosure furthermore can include an operator control which actuates the hoisting gear with reference to specifications of the operator.
Advantageously, the controller therefore includes two separate path planning modules via which trajectories for the heave compensation and for the operator control are calculated separate from each other. In particular, these trajectories can be trajectories for the position and/or velocity and/or acceleration of the hoisting gear.
Furthermore, the trajectories specified by the two separate path planning modules can be added up and serve as setpoint values for the control and/or regulation of the hoisting gear.
Furthermore, it can be provided according to the present disclosure that the division of at least one kinematically constrained quantity between heave compensation and operator control is adjustable, wherein the adjustment for example can be effected by a weighting factor by which the maximum available power and/or velocity and/or acceleration of the hoisting gear is split up between the heave compensation and the operator control.
Such division is easily possible in the heave compensation according to the present disclosure, which anyway takes account of constraints of the hoisting gear. In particular, the division of the at least one kinematically constrained quantity is taken into account as constraint of the hoisting gear. Advantageously, the operator control also takes account of at least one constraint of the drive, and in particular of the maximum admissible jerk and/or a maximum available power and/or a maximum available acceleration and/or a maximum available velocity.
According to the present disclosure, the optimization operation of the heave compensation can determine a target trajectory which is included in the control and/or regulation of the hoisting gear. In particular, as described above, the optimization operation can calculate a target trajectory of the position and/or velocity and/or acceleration of the hoisting gear, which is included in a setpoint value for a subsequent control of the hoisting gear. The optimization can be effected via a discretization.
According to the present disclosure, the optimization can be effected at each time step on the basis of an updated prediction of the movement of the load lifting point.
According to the present disclosure, the first value of the target trajectory each can be used for controlling the hoisting gear. When an updated target trajectory then is available, only the first value thereof will in turn be used for the control.
According to the present disclosure, the optimization operation can work with a lower scan rate than the control. This provides for choosing greater scan times for the calculation-intensive optimization operation, for the less calculation-intensive control, on the other hand, a greater accuracy due to lower scan times.
Furthermore, it can be provided that the optimization operation makes use of an emergency trajectory planning when no valid solution can be found. In this way, a proper operation also is ensured when a valid solution cannot be found.
The crane controller according to the present disclosure can comprise a measuring device which determines a current heave movement from the sensor data. For example, gyroscopes and/or tilt angle sensors can be employed as sensors. The sensors can be arranged at the crane or at a pontoon on which the crane is arranged, for example on the crane base and/or on a pontoon on which the load deposition position is arranged.
The crane controller furthermore can comprise a prediction device which predicts a future movement of the cable suspension point and/or a load deposition point with reference to the determined current heave movement and a model of the heave movement.
Advantageously, the model of the heave movement as used in the prediction device is independent of the properties, and in particular independent of the dynamics of the pontoon. The crane controller thereby can be used independent of the pontoon on which the crane and/or the load deposition position is arranged.
The prediction device can determine the prevailing modes of the heave movement from the data of the measuring device. In particular, this can be effected via a frequency analysis.
Furthermore, the prediction device can create a model of the heave with reference to the determined prevailing modes. With reference to this model, the future heave movement then can be predicted.
Advantageously, the prediction device continuously parameterizes the model with reference to the data of the measuring device. In particular an observer can be used, which is parameterized continuously. Particularly, the amplitude and the phase of the modes can be parameterized.
Furthermore, it can be provided that in the case of a change of the prevailing modes of the heave the model is updated.
Particularly, the prediction device as well as the measuring device can be configured such as is described in DE 10 2008 024513 A1, whose contents are fully made the subject-matter of the present application.
In the control concept according to the present disclosure, the dynamics of the load furthermore advantageously can be neglected due to the extendability of the cable. This results in a distinctly simpler structure of the controller.
The present disclosure furthermore comprises a crane with a crane controller as it has been described above.
In particular, the crane can be arranged on a pontoon. In particular, the crane can be a deck crane. Alternatively, it can also be an offshore crane, a harbor crane or a cable excavator.
The present disclosure furthermore comprises a pontoon with a crane according to the present disclosure, in particular a ship with a crane according to the present disclosure.
Furthermore, the present disclosure comprises the use of a crane according to the present disclosure and a crane controller according to the present disclosure for lifting and/or lowering a load located in water and/or the use of a crane according to the present disclosure and a crane controller according to the present disclosure for lifting and/or lowering a load from and/or to a load deposition position located in water, for example on a ship. In particular, the present disclosure comprises the use of the crane according to the present disclosure and the crane controller according to the present disclosure for deep-sea lifts and/or for loading and/or unloading ships.
The present disclosure furthermore comprises a method for controlling a crane which includes a hoisting gear for lifting a load hanging on a cable. A heave compensation at least partly compensates the movement of the cable suspension point and/or a load deposition point due to the heave by an automatic actuation of the hoisting gear. According to the present disclosure, it is provided in accordance with a first aspect that the heave compensation takes account of at least one constraint of the hoisting gear when calculating the actuation of the hoisting gear. In accordance with a second aspect, on the other hand, it is provided that the heave compensation calculates a trajectory of the position and/or velocity and/or acceleration of the hoisting gear with reference to a predicted movement of the cable suspension point, which is included in a setpoint value for a subsequent control of the hoisting gear. The method according to the present disclosure has the same advantages which have already been described with regard to the crane controller.
Furthermore, the method can be carried out such as has also been described above. In particular, the two aspects according to the present disclosure also can be combined in the method.
Furthermore, the method according to the present disclosure can be effected by a crane controller as it has been described above.
The present disclosure furthermore comprises software with code for execution as method according to the present disclosure. In particular, the software can be stored on a machine-readable data carrier. Advantageously, a crane controller according to the present disclosure can be implemented by installing the software on a crane controller.
Advantageously, the crane controller according to the present disclosure is realized electronically, in particular by an electronic control computer. The control computer advantageously is connected with sensors. In particular, the control computer can be connected with the measuring device. Advantageously, the control computer generates control signals for actuating the hoisting gear.
The hoisting gear can be a hydraulically driven hoisting gear. In accordance with the present disclosure, the control computer of the crane controller according to the present disclosure can actuate the swivel angle of at least one hydraulic displacement machine of the hydraulic drive system and/or at least one valve of the hydraulic drive system.
In one example, a hydraulic accumulator is provided in the hydraulic drive system, via which energy can be stored when lowering the load, which then is available as additional power when lifting the load.
Advantageously, the actuation of the hydraulic accumulator is effected separate from the actuation of the hoisting gear according to the present disclosure.
Alternatively, an electric drive can also be used. The same can also comprise an energy accumulator.
The present disclosure will now be explained in detail with reference to exemplary embodiments and drawings.